The Federal Aviation Administration announced a rare nationwide ground stop on Friday afternoon, in what appeared to be a major outage affecting its air traffic control system.
As of about 4:45 p.m., there were more than 7,800 flights delayed in the United States and about 350 cancellations, according to FlightAware, a flight tracking website.
This is only the third nationwide ground stop in decades. The F.A.A. issued nationwide ground stops previously on Sept. 11, 2001, in the wake of the terrorist attack on the World Trade Center in New York, and on Jan. 11, 2023, due to an outage in the F.A.A.’s system to alert pilots to safety issues.
The reason for the ground stop was not immediately clear, but an FAA spokesperson said there is a communications problem impacting Air Route Traffic Control Centers, which handle flights going across the country. Preliminary reports indicate this is not a cyberattack, according to two law enforcement officials.